# Treetop (http://treetop.rubyforge.org/) grammar for package definitions.

# Some aspects of this grammar are significantly dumber than they could be
# because:
#
#   * We want to treat statements as identically as possible to their
#     command-line equivalents.
#   * Treetop parse errors are pretty inscrutable at times and we can make
#     error messages clearer by validating a lot of the terminals ourselves.

module Fig
  grammar Fig
    rule package
      optional_ws statements:(package_statement*) optional_ws {
        def to_package(directory, build_state)
          return build_state.new_package_statement(directory, statements)
        end
      }
    end

    rule package_statement
      archive / resource / retrieve / config
    end

    rule archive
      statement_start:"archive" ws url:asset_url ws {
        def to_package_statement(build_state)
          return build_state.new_asset_statement(
            Statement::Archive, statement_start, url
          )
        end
      }
    end

    rule resource
      statement_start:"resource" ws url:asset_url ws {
        def to_package_statement(build_state)
          return build_state.new_asset_statement(
            Statement::Resource, statement_start, url
          )
        end
      }
    end

    rule asset_url
      [\S]+
    end

    rule retrieve
      statement_start:"retrieve" ws var:environment_variable_name "->" path:retrieve_path ws {
        def to_package_statement(build_state)
          return build_state.new_retrieve_statement(statement_start, var, path)
        end
      }
    end

    rule retrieve_path
      [a-zA-Z0-9_/.\[\]-]+
    end

    rule config
      statement_start:"config" ws config_name ws statements:config_statement* "end" ws {
        def to_package_statement(build_state)
          return build_state.new_configuration_statement(
            statement_start, config_name, statements
          )
        end
      }
    end

    rule config_name
      [a-zA-Z0-9_.-]+
    end

    rule config_statement
      override / include / command / path / set
    end

    rule include
      statement_start:"include" ws descriptor_string ws {
        def to_config_statement(build_state)
          return build_state.new_include_statement(
            statement_start, descriptor_string
          )
        end
      }
    end

    rule override
      statement_start:"override" ws descriptor_string ws {
        def to_config_statement(build_state)
          return build_state.new_override_statement(
            statement_start, descriptor_string
          )
        end
      }
    end

    rule path
      statement_start:("add" / "append" / "path") ws name_value:[\S]+ ws {
        def to_config_statement(build_state)
          return build_state.new_environment_variable_statement(
            Statement::Path, statement_start, name_value
          )
        end
      }
    end

    rule environment_variable_name
      [a-zA-Z0-9_]+
    end

    rule set
      statement_start:"set" ws name_value:[\S]+ ws {
        def to_config_statement(build_state)
          return build_state.new_environment_variable_statement(
            Statement::Set, statement_start, name_value
          )
        end
      }
    end

    rule command
      statement_start:"command" ws string {
        def to_config_statement(build_state)
          return build_state.new_command_statement(statement_start, string)
        end
      }
    end

    rule string
      '"' value:(!'"' . )* '"' ws
    end

    rule descriptor_string
      [\S]+
    end

    rule ws
      [ \n\r\t]+
    end

    rule optional_ws
      [ \n\r\t]*
    end
  end
end